1. Field of the Invention
The invention relates to the control of a plurality of lamps in an elevator system, and to the detection of burned-out lamps while utilizing a single microcomputer based lamp controller and a minimum number of communication lines between the controller and lamp drivers.
2. Description of the Prior Art
The power and control wiring required for the various lamps at the floors of a building associated with an elevator system, such as the hall call lamps associated with the hall call pushbuttons, and the hall lanterns, is costly to install and maintain. Thus, it is desirable to minimize the number of power and communication lines required for any one function.
One of the most troublesome problems in the maintenance and servicing of an elevator system is the detection of burned-out lamps, or other similar indicators. The detection of such failures is labor intensive, especially for lamps which are located at the various floors. Sericve personnel are required to check the associated up and down hall lanterns at each fllor, as well as the up and down hall call registered lamps associated with the up and down hall call pushbuttons at each floor. Thus, it would be desirable to be able to check the integrity of lamp control circuitry and to detect burned-out lamps automatically, providing stored records which pinpoint problems and failed lamps for maintenance personnel, without requiring a microcomputer based controller at each floor of the building.
It would further be desirable to add the capability of testing sytem integrity and detecting failed lamps, without increasing the number of signal lines in the floor-to-floor communication bus, and without occupying additional communication time slots on any existing serialized signal communication line. Occupying communication time slots by the testing and checking function would reduce the number of lamps that may be served by one bus. Finally, the system checking function must be accomplished a very little additional cost per lamp, due to the large number of lamps associated with the hall call and hall lantern functions.